The grandparent's post might be referring to an article¹ recently featured on HN which stated that complementing cow feed with less than 2% of a specific dried

The grandparent's post might be referring to an article¹ recently featured on HN which stated that complementing cow feed with less than 2% of a specific dried seaweed, called Asparagopsis, might decrease their methane production by 99%. [¹] : https://news.ycombinator.com/item?id=20711498 https://news.ycombinator.com/item?id=20711498